U.S. Bank, PNC, and all but the biggest U.S. megabanks are set to win regulatory relief, as the Federal Reserve moved Wednesday to ease post-crisis rules and regulations.

Though Wednesday’s action was in response to a new law passed by Congress, the Fed used its discretionary authority to propose further changes for several major regional banks.

Most of the Fed’s leadership, including Fed Chairman Jerome Powell and Fed Vice-Chair for Supervision Randal Quarles, who also led writing of the new rules, approved of the planned changes in a vote by the central bank's Board of Governors.

"With these proposals, banking organizations will see reduced regulatory complexity and easier compliance with no material decline in the strength of the U.S. banking system," Quarles said in prepared remarks.

Fed Governor Lael Brainard, an Obama appointee, was the lone voice of dissent. She argued that the rule changes would unnecessarily exceed the parameters set by Congress earlier this year, and could increase risks of another financial crisis and bank bailout.

"This raises the risk that taxpayers will again be on the hook,” she said.

The new regulatory law that the Fed is working to implement is the largest rewrite of financial regulations since the 2010 Dodd-Frank law passed as a reaction to the 2008 financial crisis.

The regulatory relief law, primarily written by Senate Banking Committee Chairman Mike Crapo R-Id., and signed by President Trump in May, mandated changes to rules for banks considered regional, of up to $250 billion in total assets, but not banks whose potential failure could throw the global financial system into another crisis.

The Fed’s move, if it goes through as planned, would provide lighter regulations for major banks like Capital One and U.S. Bank that are among the top 10 largest banks in the country, but don’t have the international reach nor same level of operational complexity as the top six largest banks in the U.S.

The changes represent an effort by Trump-appointed financial regulators to aim regulations more at the activities banks and other large financial institutions engage in, rather than at the business entities themselves. Most Democrats, as well as proponents of stricter financial regulations, remain skeptical of that effort. Much of the disagreement boils down to a difference of opinion over how much cash and other assets that can be easily liquidated banks should be required to hold in order to weather a crisis.

Better Markets, a nonprofit aimed at stronger financial rules, blasted the changes.

"Today’s actions by the Fed are as unjustified as they are unwise,” said Dennis Kelleher, president and CEO of the group, in a statement. “Deregulating some of the largest banks in the country will make the financial system less safe, less stable and less protected from another crash."

In addition to changing its own rules for banks, the Fed board voted to move ahead on joint proposals with the other federal banking regulators charged with ensuring the safety and soundness of the financial system.

The new rules create four new tiers of regulation for major financial firms.

The first tier is banks with more $250 billion in assets, or those of $100 billion that have more complicated, potentially riskier business models than their peers. Those banks get more tailored, lighter regulations.

Wednesday’s proposal also includes changes meant to make business easier for most banks under $250 billion. Those companies will no longer have to meet certain requirements for liquidity and mandated financial ‘stress tests,’ which gauge how they would perform in a crisis. Companies can continue stress-testing themselves, but don’t have to publicly disclose the results.

The Fed said that regulations for banks with substantial international operations or economic impact of the size that their failure could threaten the global financial system will remain largely unchanged, but set a new asset threshold of $700 billion and above for its third most-stringent tier of regulations. That allows significant room to grow for banks above $250 billion in total assets, the largest of which is U.S. Bank, at $464 billion in total assets.

Foreign banks operating in the U.S. will not see any changes from Wednesday’s proposal, but the Fed promised a rulemaking aimed at them in the near future.

The Fed’s new draft rules are available for public comment; the Fed and other bank regulators will likely finalize them early next year, though it may make some changes based on feedback.